Pedaling sensing device of electric bicycle

ABSTRACT

A pedaling sensing device of an electric bicycle is configured to connect to a motor and includes a crank axle, a first gearwheel disposed around the crank axle, a second gearwheel disposed around the first gearwheel, a sensing unit, an assisting unit, and a chain wheel. The crank axle has first bevel teeth, and the first gearwheel has a first transmission structure and second bevel teeth matching the first bevel teeth. The second gearwheel has a second transmission structure matching the first transmission structure. When the crank axle is driven by a force to rotate, the first gearwheel, second gearwheel and chain wheel are carried to rotate. The first gearwheel also moves with respect to the crank axle along the axial direction, so the sensing unit can sense the applied force. Then, the motor drives the assisting gearwheel and chain wheel to rotate, thereby achieving assisting riding effect.

CROSS REFERENCE TO RELATED APPLICATIONS

This Non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 108210360 filed in Taiwan, Republic of China on Aug. 6, 2019, the entire contents of which are hereby incorporated by reference.

BACKGROUND Technology Field

This disclosure relates to a sensing device and, in particular, to a pedaling sensing device of an electric bicycle with an electric powering function that can transfer the force applied to the crank axle into a sensing signal.

Description of Related Art

Bicycles are commonly used by people as a means of travel. Since riding bicycles can achieve exercise effects and save energy, more and more people like to go out by bicycle. However, when riding on a hill or mountain or riding for a long distance, the rider may not enjoy the riding trip. Besides, the older riders may easily feel tired when riding bicycles. Therefore, in order to make people ride more smoothly and easier, an electric bicycle (also known as an e-bike) is provided on the market. The electric bicycle is a bicycle with an integrated electric motor, which can be used for propulsion, to assist the rider's pedal-power, thereby making the riders easier and more power saving. In general, the electric bicycle comprises a pedaling sensing device for detecting the rider's pedaling force and then driving the motor to generate the assisting power as the pedaling force is detected.

Therefore, for the sake of the large requirements for electric bicycles, a novel pedaling sensing device of an electric bicycle is provided that can correctly sense the user's pedaling force for driving the motor to operate.

SUMMARY

In view of the foregoing, an objective of this disclosure is to provide a pedaling sensing device of an electric bicycle having a novel structure and a good sensing effect.

This disclosure provides a pedaling sensing device of an electric bicycle, which is configured to connect to a motor of the electric bicycle, and comprises a crank axle, a first gearwheel, a second gearwheel, a sensing unit, an assisting unit, and a chain wheel.

The crank axle extends along an axial direction and comprises an outer surface, and a plurality of first bevel teeth are disposed around the outer surface. The first gearwheel is disposed around the outer surface of the crank axle and comprises a first inner annulus surface and a first outer annulus surface opposite to the first inner annulus surface. The first inner annulus surface is formed with a plurality of second bevel teeth matching the first bevel teeth, and the first outer annulus surface is formed with a first transmission structure.

The second gearwheel is disposed around the first outer annulus surface of the first gearwheel. The second gearwheel comprises a second inner annulus surface disposed around the first outer annulus surface, and the second inner annulus surface is formed with a second transmission structure matching the first transmission structure. The sensing unit is disposed around the crank axle and located adjacent to the first gearwheel, and the sensing unit is signally connected with the motor. The assisting unit comprises an assisting gearwheel disposed around the crank axle, and the motor is configured to drive the assisting gearwheel to rotate. The chain wheel is disposed around the crank axle and connects to the assisting unit.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will become more fully understood from the detailed description and accompanying drawings, which are given for illustration only, and thus are not limitative of the present disclosure, and wherein:

FIG. 1 is an exploded perspective view of a pedaling sensing device of an electric bicycle according to a first embodiment of this disclosure;

FIG. 2 is an exploded perspective view of parts of the first embodiment;

FIG. 3 is a sectional view of an assembled pedaling sensing device of the first embodiment;

FIG. 4 is an exploded perspective view of a pedaling sensing device of an electric bicycle according to a second embodiment of this disclosure;

FIG. 5 is a sectional view of an assembled pedaling sensing device of the second embodiment;

FIG. 6 is an enlarged sectional view of a part of FIG. 5; and

FIG. 7 is a sectional view similar to FIG. 6, wherein the first gearwheel of the second embodiment moves rightward from the position as shown in FIGS. 5 and 6.

DETAILED DESCRIPTION OF THE DISCLOSURE

The present disclosure will be apparent from the following detailed description, which proceeds with reference to the accompanying drawings, wherein the same references relate to the same elements.

Referring to FIGS. 1 to 3, in a first embodiment of this disclosure, a pedaling sensing device of an electric bicycle, which is configured to connect to a motor 10 of the electric bicycle, comprises a crank axle 1, a first gearwheel 2, a second gearwheel 3, a sensing unit 4, a thrust bearing 5, an elastic element 6, an assisting unit 7, and a chain wheel 8.

The crank axle 1 extends along an axial direction A and comprises an outer surface 11. A plurality of first bevel teeth 111 are disposed annularly around the outer surface 11. Each end of the crank axle 1 is connected to a crank (not shown), and the crank is further connected to a pedal (not shown).

In this embodiment, the first gearwheel 2 is composed of two portions including a main body portion 21 and a ring portion 22 disposed at one end of the main body portion 21. In practice, the main body portion 21 and the ring portion 22 can be integrated as one piece, or the ring portion 22 can be omitted. The first gearwheel 2 is disposed around the outer surface 11 of the crank axle 1. The first gearwheel 2 comprises a first inner annulus surface 23 and a first outer annulus surface 24. The first inner annulus surface 23 has an annular shape and is disposed toward the outer surface 11 of the crank axle 1. The first outer annulus surface 24 is located opposite to the first inner annulus surface 23. The first inner annulus surface 23 is formed with a plurality of second bevel teeth 231 for engaging with (matching) the first bevel teeth 111. The first outer annulus surface 24 is formed with a first transmission structure 240. The first transmission structure 240 comprises a plurality of first straight teeth 241 disposed around the first outer annulus surface 24 and extending along the axial direction A. Since the second bevel teeth 231 of the first gearwheel are engaged with the first bevel teeth 111 of the crank axle, when the crank axle 1 rotates, the first gearwheel 2 can be carried to rotate, thereby providing a force for generating an axial displacement of the first gearwheel 2. Accordingly, when the first gearwheel 2 is rotated, it can be also moved with respect to the crank axle 1 along the axial direction A.

The second gearwheel 3 is disposed around the first outer annulus surface 24 of the first gearwheel 2. In this embodiment, the second gearwheel 3 comprises a second inner annulus surface 31 and a second outer annulus surface 32. The second inner annulus surface 31 is disposed around the first outer annulus surface 24, and the second outer annulus surface 32 is disposed opposite to the second inner annulus surface 31. The second inner annulus surface 31 is formed with a second transmission structure 310 matching the first transmission structure 240. The second transmission structure 310 comprises a plurality of second straight teeth 311 for engaging with the first straight teeth 241. Accordingly, the first gearwheel 2 can carry the second gearwheel 3 to rotate. At least a bearing 33 is disposed adjacent to the second gearwheel 3 for making the rotation of the second gearwheel smoother.

To be noted, in practice, the first transmission structure 240 and the second transmission structure 310 can be formed with another type of structures such as the bevel teeth or wavy teeth. Accordingly, the first gearwheel 2 can still carry the second gearwheel 3 to rotate.

The sensing unit 4 is installed around the crank axle 1 and located adjacent to the first gearwheel 2, and the sensing unit 4 is signally connected with the motor 10. Specifically, the sensing unit 4 of the first embodiment comprises a pressure sensing element 41 disposed around the crank axle 1 for sensing a pressing force from the first gearwheel 2.

The thrust bearing 5 is disposed around the crank axle 1 and is located between the first gearwheel 2 and the pressure sensing element 41. The elastic element 6 is a disc spring. The elastic element 6 is disposed around the crank axle 1 and is located at one side of the first gearwheel 2 away from the thrust bearing 5. In practice, the elastic element 6 pushes the first gearwheel 2 toward the thrust bearing 5, so that the first gearwheel 2 can apply a predetermined pressing force to the pressure sensing element 41 through the thrust bearing 5.

The assisting unit 7 comprises an assisting gearwheel 71, a connecting base 72 and a one-way bearing 73. The assisting gearwheel 71 is disposed around the crank axle 1, wherein the motor 10 is configured to drive the assisting gearwheel 71 to rotate. The connecting base 72 is disposed around the crank axle 1 and is located between the crank axle 1 and the assisting gearwheel 71. The one-way bearing 73 is disposed around the connecting base 72 and is located between the connecting base 72 and the assisting gearwheel 71. The chain wheel 8 is disposed around the crank axle 1 and is connected to the connecting base 72 of the assisting unit 7.

For example, when the rider pedals forwardly to drive the crank axle 1 to rotate forwardly, the crank axle 1 can carry the engaged first gearwheel 2 and second gearwheel 3 to rotate, and thus carry the connecting base 72 as well as the chain wheel 8 to rotate. Herein, the crank axle 1 is applied with a force, which is a torque transferred from the pedaling of the rider. Accordingly, the propulsion of the electric bicycle can be provided by the pedaling of the rider.

Moreover, when the rider pedals to provide the propulsion of the electric bicycle, the applied force can also drive the crank axle 1 to rotate the first gearwheel 2. Since the second bevel teeth 231 of the first gearwheel 2 are engaged with the first bevel teeth 111 of the crank axle 1, a force along the axial direction A can be applied to the first gearwheel 2, thereby pushing the first gearwheel 2 to move with respect to the crank axle 1 along the axial direction A. To be noted, the movement of the first gearwheel 2 is very small, so it is not shown in the figures. In the first embodiment, the design of the extension directions of the first bevel teeth 111 and the second bevel teeth 231 allows the first gearwheel 2 to move toward the pressure sensing element 41 along the axial direction A. Then, the first gearwheel 2 pushes the thrust bearing 5 so as to generate a pressing force to press the pressure sensing element 41. When the pressing force increases, the pressure sensing element 41 can sense the applied force and then transform the sensed force into an electrical signal, which is then sent to the motor 10 for controlling the motor to operate. Accordingly, the motor 10 can be enabled to drive the assisting gearwheel 71 to rotate. Then, the connecting base 72 can transmit the power of the motor 10 to the chain wheel so as to provide the assisting power to rotate chain wheel.

In other words, when the rider pedals to rotate the chain wheel 8, the first gearwheel 2 can also apply a force to the sensing unit 4. Once the sensing unit 4 senses the applied force, it can control the motor 10 to operate for assisting the rotation of the chain wheel, thereby achieving the desired assisting riding effect. Accordingly, the rider can ride the electric bicycle easier. To be noted, when the motor 10 drives the assisting gearwheel 71 to rotate through the one-way bearing 73 of the assisting unit 7, the crank axle 1 is not affected. When the on-way bearing 73 rotates the assisting gearwheel 71, the connecting base 72 and the chain wheel are carried to rotate in one-way. If the rider stops pedaling, the first gearwheel 2 will return to the original position as shown in FIG. 3, and the motor 10 stops operation.

Referring to FIGS. 4 to 6, the structure of the pedaling sensing device of an electric bicycle of a second embodiment of this disclosure is mostly the same as that of the first embodiment. Different from the first embodiment, the extension directions of the first bevel teeth 111 of the crank axle 1 and the second bevel teeth 231 of the first gearwheel 2 are opposite to those of the first embodiment. Accordingly, when the rider pedals forwardly to carry the crank axle 1 to rotate forwardly. That is, when the (pedaling) force is applied to the crank axle 1, the first gearwheel 2 can be driven by the crank axle 1 to rotate and move toward the assisting gearwheel 71 along the axial direction A.

The sensing unit 4 of the second embodiment comprises a magnet 42 disposed on the first gearwheel 2 and two magnetic sensing elements 43. The magnet 42 is correspondingly rotated with the first gearwheel 2, and the magnetic sensing elements 43 are disposed adjacent to the crank axle 1 for sensing a magnetic flux variation. The magnetic sensing elements 43 are signally connected to the motor 10. The first gearwheel 2 is located between the magnetic sensing element 43 and the assisting gearwheel 71.

In the second embodiment, the pedaling sensing device comprises a plurality of elastic elements 6, which are disc springs arranged along the axial direction A and disposed around the crank axle 1. The elastic elements 6 are located between the first gearwheel 2 and the assisting gearwheel 71, and are configured for pushing the first gearwheel 2 toward the magnetic sensing elements 43.

With reference to FIGS. 5, 6 and 7, in the second embodiment, the magnetic sensing element 43 senses the magnetic flux variation caused by the movement of the magnet 42 so as to sense the applied (pedaling) force. Specifically, when the force is provided to rotate the crank axle 1 and the first gearwheel 2 is rotated along with the crank axle 1, the magnet 42 is also rotated and is moved along the axial direction A from the position as shown in FIG. 6. To be noted, the movement of the magnet 42 is very small as shown in FIG. 6 (a distance d). The magnet 42 is moved toward the assisting gearwheel 71 to reach the position as shown in FIG. 7, so the magnetic sensing element 43 can sense the magnetic flux variation so as to determine that the force is applied. Then, the magnetic sensing element 43 controls to enable the motor 10 for outputting a power to assist the rotation of the assisting gearwheel 71 and the chain wheel 8, thereby achieving the assisting riding effect. If the rider stops pedaling, the first gearwheel 2 will return to the original position as shown in FIG. 6, and the motor 10 stops operation.

As mentioned above, the first bevel teeth 111 of the crank axle 1 match the second bevel teeth 231 of the first gearwheel 2, and the first transmission structure 240 of the first gearwheel 2 matches the second transmission structure 310 of the second gearwheel 3. Accordingly, when the force is applied to rotate the crank axle 1, the first gearwheel 2 is carried to rotate and is moved along the axial direction A, so that the sensing unit 4 can sense the applied force and then control the motor 10 to provide the assisting power. This disclosure provides a novel structure, and the sensing unit 4 has a good sensing ability, thereby achieving the effect of easy riding.

Although the disclosure has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments, will be apparent to persons skilled in the art. It is, therefore, contemplated that the appended claims will cover all modifications that fall within the true scope of the disclosure. 

What is claimed is:
 1. A pedaling sensing device of an electric bicycle, which is configured to connect to a motor of the electric bicycle, comprising: a crank axle extending along an axial direction and comprising an outer surface, wherein a plurality of first bevel teeth are disposed around the outer surface; a first gearwheel disposed around the outer surface of the crank axle and comprising a first inner annulus surface and a first outer annulus surface, wherein the first inner annulus surface is formed with a plurality of second bevel teeth matching the first bevel teeth, and the first outer annulus surface is formed with a first transmission structure; a second gearwheel disposed around the first outer annulus surface of the first gearwheel, wherein the second gearwheel comprises a second inner annulus surface disposed around the first outer annulus surface, and the second inner annulus surface is formed with a second transmission structure matching the first transmission structure; a sensing unit disposed around the crank axle and located adjacent to the first gearwheel, wherein the sensing unit is signally connected with the motor; an assisting unit comprising an assisting gearwheel disposed around the crank axle, wherein the motor is configured to drive the assisting gearwheel to rotate; and a chain wheel disposed around the crank axle and connecting to the assisting unit.
 2. The pedaling sensing device according to claim 1, wherein when a force is applied to rotate the crank axle, the first gearwheel, the second gearwheel and the chain wheel are carried to rotate, the first gearwheel also moves with respect to the crank axle along the axial direction while rotating, such that the sensing unit senses the applied force so as to control the motor to drive the assisting gearwheel to rotate, and the assisting unit transmits an assisting power from the motor to the chain wheel for assisting to rotate the chain wheel.
 3. The pedaling sensing device according to claim 1, wherein the assisting unit further comprises a connecting base disposed around the crank axle, the connecting base is located between the crank axle and the assisting gearwheel and connected to the chain wheel, and the connecting base carries the chain wheel to rotate as the assisting gearwheel rotates.
 4. The pedaling sensing device according to claim 3, wherein the assisting unit further comprises a one-way bearing disposed around the connecting base, the one-way bearing is located between the connecting base and the assisting gearwheel, and the one-way bearing drives the assisting gearwheel to rotate so as to carry the connecting base to rotate in one way.
 5. The pedaling sensing device according to claim 2, wherein the sensing unit further comprises a pressure sensing element disposed around the crank axle, and the first gearwheel moves toward the pressure sensing element as the first gearwheel rotates along with the crank axle, thereby increasing a pressing force applied to the pressure sensing element, so that the sensing unit senses the applied force.
 6. The pedaling sensing device according to claim 5, further comprising a thrust bearing disposed around the crank axle, wherein the thrust bearing is located between the first gearwheel and the pressure sensing element.
 7. The pedaling sensing device according to claim 6, further comprising an elastic element disposed around the crank axle, wherein the elastic element is located at one side of the first gearwheel away from the thrust bearing, and the elastic element pushes the first gearwheel toward the thrust bearing.
 8. The pedaling sensing device according to claim 7, wherein the elastic element is a disc spring.
 9. The pedaling sensing device according to claim 2, wherein the sensing unit comprises a magnet disposed on the first gearwheel and a magnetic sensing element, the magnetic sensing element is disposed adjacent to the crank axle for sensing a magnetic flux variation, and the magnet rotates and moves along the axial direction as the first gearwheel rotates along with the crank axle, such that the magnetic sensing element senses the magnetic flux variation so as to sense the applied force.
 10. The pedaling sensing device according to claim 9, wherein the first gearwheel is located between the magnetic sensing element and the assisting gearwheel, and the first gearwheel moves toward the assisting gearwheel along the axial direction as the first gearwheel rotates along with the crank axle.
 11. The pedaling sensing device according to claim 10, further comprising an elastic element disposed around the crank axle, wherein the elastic element is located between the first gearwheel and the assisting gearwheel, and the elastic element pushes the first gearwheel toward the magnetic sensing element.
 12. The pedaling sensing device according to claim 11, wherein the elastic element is a disc spring.
 13. The pedaling sensing device according to claim 1, wherein at least one bearing is disposed adjacent to the second gearwheel.
 14. The pedaling sensing device according to claim 1, wherein the first transmission structure comprises a plurality of straight teeth.
 15. The pedaling sensing device according to claim 1, wherein the first transmission structure comprises a plurality of bevel teeth.
 16. The pedaling sensing device according to claim 1, wherein the first transmission structure comprises a plurality of wavy teeth.
 17. The pedaling sensing device according to claim 1, wherein each of two ends of the crank axle is connected to a crank, and the crank is further connected to a pedal.
 18. The pedaling sensing device according to claim 1, wherein the first gearwheel comprises a main body portion and a ring portion disposed at one end of the main body portion.
 19. The pedaling sensing device according to claim 18, wherein the main body portion and the ring portion are integrated as one piece.
 20. The pedaling sensing device according to claim 1, wherein the first gearwheel comprises a main body portion. 